function tamper_img = rand_tamper(stego_cover,density)
%UNTITLED2 此处显示有关此函数的摘要
%   density修改密度，10,20,30,40
[col,raw]=size(stego_cover);
tamper_num=round(col*raw*density/100);
for w=1:tamper_num
    i= randi([1,col],1,1);
    j= randi([1,raw],1,1);
    x= randi([0,255],1,1);
    stego_cover(i,j)=x;
end
tamper_img=stego_cover;
end

